Top musical acts include Simone Felice of the Felice Brothers, and Simi Stone and her all-star band Gail Ann Dorsey, Zachary Alford, (longtime collaborators of David Bowie), Sara Lee (Gang of Four) and David Baron.

The weekend concludes with a concert by British space-rock band Spiritualized at 9:30 p.m. Sunday at Old Dutch Church on Wall Street.

Wristbands are $25 for the weekend, free for young children. No single-day passes. Wristbands are available at the O+ headquarters and merchandise booth at the intersection of North Front and Wall Streets throughout the festival.

The fourth annual O+ Festival celebrates the art of medicine and the medicine of art in an even more expansive way this weekend.

“Whether or not you have health insurance doesn’t mean you are healthy,” says painter and festival co-organizer Joe Concra. “Even if the Affordable Care Act was a single-payer system, there’d still be a need for the O+ Festival because we’re talking about keeping people well.”

The three-day festival takes over venues in Uptown Kingston with more than 80 art displays, 40 musical acts, and more than 90 medical and alternative care practitioners at Academy Green and Wall Street. New this year is the ExplO+re program, offering yoga and movement classes all weekend at St. Joseph’s School on Wall Street.

The advent of the Affordable Care Act brings teams of educators from the Actor’s Fund, the Future of Music Coalition, and the Grammy Foundation’s MusiCares to counsel musicians and artists on affordable health insurance options.

“We talk a lot about insurance in our society but we don’t talk about wellness and care,” Concra said. “So O+ educates the community that health isn't just health insurance. It’s movement. It’s food. It’s connecting.”

Participating artists and musicians are seen by a medical doctor, given a basic physical and then continue on to treatments, ranging from dentistry and eye exams to massage and acupuncture, perhaps with referrals from the doctor for other kinds of follow-up care.

“It says something that the muralist Gaia came here to work on his mural for six days and left with his teeth fixed and some basic medical needs addressed,” Concra said.

Art Chandler, a physician at Columbia Memorial Hospital in Hudson, set up the screenings this year for 264 musicians, artists and volunteers. “Last year it was 150,” Chandler said. It’s a relaxed process because the festival demographic is relatively young and healthy. “We might educate them on STD prevention, quitting smoking or alleviating anxiety, but if there is an issue, we have medical centers from Kingston to lower Manhattan who are offering discounts or free services for more refined follow-up care.”

This is the first year that O+ will offer a sister festival on Nov. 15-17 in San Francisco and has fielded inquiries from cities in Pennsylvania and Vermont.

Chandler and other primary care physicians are exploring the feasibility of opening a year-round O+ clinic in Uptown Kingston.

“We are a band of passionate people in a protean effort to get this to happen,” Chandler said. “We’re struggling with the funding, but we’d love to have a street presence to house the clinic and make the fest a community celebration of art, music and medicine.”